I have a 94 4.0 and I am getting a very loud tapping from the valve cover area whenever I first start it up. It lasts anywhere from 1 to 5 minutes and is tune with the RPMs. After a bit, it instantly just quits. It seems to me like I have a sticking valve. Any suggestions such as Seafoam, Marvel Mystery Oil, Dura Lube, etc? Should I not drive it the 1500 miles I was going to this next week, or is it really not that big of a deal for a motor with 140k miles? TIA, JP
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Sticking Valve??
- Thread starter JKTXJ
- Start date
- Location
- Terra Firma
It could be a sticky lifter (not valve), but on a '94 it's more likely piston slap, and there's not a thing you can do about it short of replacing the pistons. Doesn't appear to be harmful, they all have it, so go on your trip.
Note: The piston slap problem was a result of Chrysler attempting to further optimize a design that had already been optimized by AMC. Chrysler wanted to save as much weight as possible, so they shortened the length of the piston skirts slightly. This allows the pistons to rock on the wrist pins when cold. They expand when they get warm, and that quiets the noise because then they run truer in the bores.
Note: The piston slap problem was a result of Chrysler attempting to further optimize a design that had already been optimized by AMC. Chrysler wanted to save as much weight as possible, so they shortened the length of the piston skirts slightly. This allows the pistons to rock on the wrist pins when cold. They expand when they get warm, and that quiets the noise because then they run truer in the bores.
Thanks Eagle! I hear the piston slap too but this is different, probably a lifter like you say. It is a very loud tap, tap, tap, tap, tap, tap, tap, tap, tap, tap coming right from under the valve cover. Anyone had luck with Seafoam on something like this? Any other tricks?
JP
JP
RichP
NAXJA Forum User
- Location
- Effort, Pa
Seafoam, mobil-1, Syntec will clean out most gummed up lifters. The crud is just stopping them from filling up faster with oil... The mobil-1 and Syntec are longer term solutions, the seafoam and other cleaners will work faster.
StuckXJ
NAXJA Forum User
- Location
- Massachusetts
Were can I pick up some seafoam? I havn't really looked anywear other than wally world tho.
-Steve D
-Steve D
Ed in North Ga.
NAXJA Forum User
- Location
- Georgia/ Hiawassee
on my 89, I tried everything you could imagine- i found out marvel mystery oil will cause gaskets to leak- that about covers that. I tried light oil, heavy oil, cleaners, conditioners, top end treatment, and foamy....
it went away on its own- lasted about 15,000 miles I guess.
scary sound, isnt it.
it went away on its own- lasted about 15,000 miles I guess.
scary sound, isnt it.
- Location
- Louisville, IL
You can get seafoam at NAPA. JIM.
